Patch "perf bpf: Move the declaration of struct rq" has been added to the 6.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf bpf: Move the declaration of struct rq

to the 6.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-bpf-move-the-declaration-of-struct-rq.patch
and it can be found in the queue-6.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 660b359c2200b4d839765db2779af847dbc646ff
Author: Ian Rogers <irogers@xxxxxxxxxx>
Date:   Thu Jun 22 21:14:03 2023 -0700

    perf bpf: Move the declaration of struct rq
    
    [ Upstream commit 5c45b210479bffe068d38902fcdcb52c4c60a264 ]
    
    struct rq is defined in vmlinux.h when the vmlinux.h is generated,
    this causes a redefinition failure if it is declared in
    lock_contention.bpf.c. Move the definition to vmlinux.h for
    consistency with the generated version.
    
    Fixes: 760ebc45746b ("perf lock contention: Add empty 'struct rq' to satisfy libbpf 'runqueue' type verification")
    Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
    Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
    Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
    Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: James Clark <james.clark@xxxxxxx>
    Cc: Mark Rutland <mark.rutland@xxxxxxx>
    Cc: Yang Jihong <yangjihong1@xxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
    Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
    Cc: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
    Cc: Ingo Molnar <mingo@xxxxxxxxxx>
    Cc: bpf@xxxxxxxxxxxxxxx
    Link: https://lore.kernel.org/r/20230623041405.4039475-3-irogers@xxxxxxxxxx
    Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index 1d48226ae75d4..8d3cfbb3cc65b 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -416,8 +416,6 @@ int contention_end(u64 *ctx)
 	return 0;
 }
 
-struct rq {};
-
 extern struct rq runqueues __ksym;
 
 struct rq___old {
diff --git a/tools/perf/util/bpf_skel/vmlinux.h b/tools/perf/util/bpf_skel/vmlinux.h
index c7ed51b0c1ef9..ab84a6e1da5ee 100644
--- a/tools/perf/util/bpf_skel/vmlinux.h
+++ b/tools/perf/util/bpf_skel/vmlinux.h
@@ -171,4 +171,14 @@ struct bpf_perf_event_data_kern {
 	struct perf_sample_data *data;
 	struct perf_event	*event;
 } __attribute__((preserve_access_index));
+
+/*
+ * If 'struct rq' isn't defined for lock_contention.bpf.c, for the sake of
+ * rq___old and rq___new, then the type for the 'runqueue' variable ends up
+ * being a forward declaration (BTF_KIND_FWD) while the kernel has it defined
+ * (BTF_KIND_STRUCT). The definition appears in vmlinux.h rather than
+ * lock_contention.bpf.c for consistency with a generated vmlinux.h.
+ */
+struct rq {};
+
 #endif // __VMLINUX_H